1. Field of Industrial Application
The present invention relates to a hydrogenation catalyst having a high activity and a high selectivity and comprising copper, iron and aluminum atoms, and a process for producing the same.
2. Description of the Related Arts
A higher alcohol has been produced by reducing a higher fatty acid methyl ester at a high temperature under a high hydrogen pressure.
A copper-chromium oxide catalyst has hitherto been used for this reaction, and this catalyst is usually called a copper-chromite catalyst. The process is described in Industrial and Engineering Chemistry, vol. 26, 878 (1936), and up to now, no significant progress has been made on the process.
The above-described catalyst has a serious drawback in that a large amount of a hexavalent chromium ion is discharged in the production of the catalyst. In order to prevent environmental pollution, the heavy metals are collected by a suitable method. However, no final treatment method for a heavy metal sludge produced in this method has been established as of yet.
Copper-iron-aluminum catalysts produced by various processes have been proposed for the purpose of solving this problem (see Japanese Patent Laid-Open No. 92395/1978, Japanese Patent Laid-Open No. 8820/1980 and Japanese Patent Publication No. 50775/1983).
These catalysts are superior to the conventional copper-chromite catalyst in the activity, selectivity and durability but suffer from production problems. Such problems include the necessary use of large-size filtration equipment due to a low filtration rate in the collection of a catalyst from a catalyst precipitate slurry (see Japanese Patent Laid-Open Nos. 92395/1978 and 8820/1980), difficult filtration due to remarkable atomization of the catalyst during withdrawal of the reaction product after the reaction from a high-pressure state to an atmospheric state, and the treatment of urea waste water and ammonia waste water due to the use of urea as a catalyst precipitant (see Japanese Patent Publication No. 50775/1983).